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961.
The first luminescent rhenium(I)-gold(I) hetero organometallics, Re{phenAu(PPh3)}(CO)3Cl (3) and Re{(PPh3)AuphenAu(PPh3)}(CO)3Cl (4), have been prepared using the gold(I) complex AuCl(PPh3) (PPh3 = triphenylphosphine) and the novel rhenium(I) complexes Re(phenH)(CO)3Cl (5) (phenH = 3-ethynyl-1,10-phenanthroline) or Re(HphenH)(CO)3Cl (6) (HphenH = 3,8-bis(ethynyl)-1,10-phenanthroline). All the present rhenium(I) complexes 3-6 were revealed to possess a facial configuration (fac-isomer) with respect to the three carbonyl ligands. The main frameworks for these new gold(I) organometallics were constructed by the Au-C σ-bonding (with the η1-type coordination) between the ethynylphenanthrolines and the Au(I) phosphine unit. Re(I)-Au(I) heterometallics 3 and 4 have shown single phosphorescence from the 3MLCT excited state and this observation can be interpreted in terms of the efficient intramolecular energy transfer from the Au(I) unit to the Re(I) unit. 相似文献
962.
The angular intensity distributions of CO and N(2) molecules scattered from a LiF(001) surface have been measured as functions of surface temperature, incident translational energy, and incident azimuthal direction affecting surface corrugation at a high resolution. Although both molecules have the same molecular mass and linear structure, only the CO molecule shows a rainbow feature in its scattering pattern, while the N(2) molecule shows a single peak distribution. From the comparisons of the obtained results with the calculated predictions based on the newly developed classical theory of the ellipsoid-washboard model, the differences in scattering distribution are attributed to the effects of molecular anisotropy and center-of-mass position. With an increase in the extent of the molecular anisotropy such as that of N(2) and CO as compared with rare-gas atoms, the summation of several scattering distributions depending on molecular orientation results in smearing the rainbow scattering on the corrugated surface. This smearing effect, however, attenuates when center-of-mass position deviates from the molecular center, as that for CO. 相似文献
963.
The applicability of 0.05 mol kg(-1) potassium hydrogen phthalate (KHPh(S), S=the solvent under study) as reference value pH standard (RVS) was studied in water-organic solvent mixtures. Phthalic acid in various aqueous organic solvent mixtures was titrated potentiometrically with Bu(4)NOH (MeOH), using a pH-ISFET and a glass electrode as pH-sensors, and the buffer capacity of the HPh(-) solution was roughly estimated from the difference between the first and second half-neutralization potentials. The influence of potassium ion to the buffer capacity was also studied, titrating KHPh and Et(4)NHPh with CF(3)SO(3)H and Bu(4)NOH (MeOH) and comparing the titration curves. The KHPh solution loses its buffer capacity if the solvent mixture has an aprotic property. For aqueous mixtures of protophilic aprotic solvents (e.g. DMSO and DMF), it is unsuitable as RVS if the water content is less than ca. 40 (v/v)%. The necessity of selecting subsidiary pH standard(s) is suggested for the solvent systems in which KHPh is inapplicable. 相似文献
964.
M. Yamamoto Y. Yamauchi K. Chatani S. Igarashi K. Komura K. Ueno M. Sakanoue 《Journal of Radioanalytical and Nuclear Chemistry》1991,147(1):165-176
In order to investigate the sedimentary behaviour of neptunium,237Np together with Pu isotopes and241Am have been measured for the sediment cores collected from Lake Mikata (freshwater) and from Lake Kugushi (brakish water) both belonging to the Mikata Five Lakes, and from Nyu Bay (sea water). In all sediment core samples237Np was detected, and its concentrations were far below those of239,240Pu and241Am measured for the same samples. Inventories of237Np in Lake Mikata, Lake Kugushi and Nyu Bay were estimated to be 0.53, 0.29 and 0.34 MBq/km2, respectively. The activity ratio of237Np/239,240Pu calculted from the inventories in each sediment core was 0.29% for Lake Mikata, 0.15% for Lake Kugushi and 0.10% for Nyu Bay. These values except for the value for Lake Mikata are two or three times lower than the value of 0.3–0.4% observed for surface soils of 0–20 cm depth, suggesting that Np is more soluble compared with Pu. 相似文献
965.
Hiroyuki Yamamoto Ayako Nishida Tomoyuki Takimoto Akira Nagai 《Journal of polymer science. Part A, Polymer chemistry》1990,28(1):67-74
Poly(L -ornithine) having azo aromatic side chain was synthesized by the water-soluble carbodiimide procedure. The photochemical properties of the azo polypeptide poly[Nδ-p-(phenylazo)benzoyl-L -ornithine] (PPABLO) was investigated by absorption and circular dichroism spectroscopy in hexafluoro-2-propanol (HFIP). The photochromism of the dichroic bands in the visible and ultraviolet wavelength regions was found to be reversible as a function of irradiation time at different wavelengths due to the photostationary state (about 70% trans)–cis photoisomerization of the azo aromatic moieties. The reversible photoinduced solubility change was also studied. On irradiation PPABLO is soluble under ultraviolet light (cis) and precipitate under visible light (70% trans) in HFIP–water. A discussion was presented that includes results on azo aromatic poly(L -lysine). 相似文献
966.
Toshio Masuda Toru Takahashi Kaoru Yamamoto Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1982,20(9):2603-2610
Phenylacetylene was polymerized by WCl6·Ph4Sn (1:1) in 1,4-dioxane to provide in high yield a polymer whose molecular weight reached 1 × 105. The polymerization also proceeded in other oxygen-containing solvents (ethers, esters, and ketones) but the polymer molecular weights were lower than 1 × 104. Certain hydrocarbon solvents such as cyclohexene, tetralin, and indan also afforded high-molecular-weight polyphenylacetylene [M n = (5–8) × 104], as compared with those (M n ≤ 1.5 × 104) obtained in conventional aromatic hydrocarbons like benzene. A high polymer (M n = 1.6 × 105) was also formed from β-naphthylacetylene in 1,4-dioxane. It was inferred that the active hydrogens of these solvents prevent the formed polymer from being decomposed by a radical mechanism and/or modify the nature of active species. 相似文献
967.
Arpansiree Wongmekiat Satoko Yoshimatsu Yuichi Tozuka Kunikazu Moribe Keiji Yamamoto 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):29-32
Drugs with poor water solubility were co-ground with cyclodextrins (CDs) to create nanoparticles with improved solubility characteristics. Indomethacin (IDM), furosemide (FRM) and naproxen (NAP) were co-ground with β-CD at the molar ratio of 2:1 (CD:drug). Co-grinding of a drug with CD resulted in not only the formation of drug nanoparticles but also the solubilization of the drug by inclusion complex formation with CD in aqueous media. The nanoparticle fraction of IDM, and FRM from ground mixtures prepared with β-CD was as high as 60–70% while the solubilization fraction was less than 10%. In contrast, β-CD–NAP ground mixture showed a large fraction, 48%, for drug solubilization and only 4% for nanoparticle formation. Furosemide ground mixtures prepared with α-CD, β-CD and γ-CD showed comparatively high nanoparticle fraction while the solubilization fraction was around 10%. Both the nanoparticle fraction and the solubilization fraction were greater in the IDM–β-CD system than those in γ-CD and α-CD systems. The nanoparticle formation of NAP depended on the types of CD used as a co-grinding additive. Naproxen nanoparticles could be prepared by co-grinding NAP and α-CD, while the solubilization of NAP tended to improve when β-CD or γ-CD was used. 相似文献
968.
Y. Suzuki T. Nankawa T. Yoshida T. Ozaki T. Ohnuki A. J. Francis S. Tsushima Y. Enokida I. Yamamoto 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(2):199-204
Summary We have investigated the structure of Eu(III)-citrate complexes in aqueous solution and their degradability by Pseudomonas fluorescens. Analysis of 1:1, 1:2, and 1:5 Eu(III):citrate solutions at pH 7 by electrospray ionization mass spectrometry (ESI-MS) showed
that the 2:2 Eu(III)-citrate complex is the predominant complex species at a low citrate/Eu(III) ratio, while at a high ratio,
a 1:2 Eu(III)-citrate complex is formed preferably. Studies on the biodegradation of Eu(III)-citrate complex by P. fluorescens have shown that a 2:2 Eu(III)-citrate complex is resistent to degradation while a 1:2 complex transforms to a 2:2 complex
with the degradation of excess citric acid. 相似文献
969.
Tonegawa H Kuboe Y Amaike M Nishida A Ohkawa K Yamamoto H 《Macromolecular bioscience》2004,4(5):503-511
Poly(L-lysine)s having an Nepsilon-substituted tetrapeptide, Lys-Gly-Tyr-Gly, were synthesized by the coupling of the protected tetrapeptide active ester, Boc-Lys(Z)-Gly-Tyr(Bzl)-Gly (4-hydroxyphenyl)dimethylsulfonium methylsulfate and Nepsilon-group of the poly(L-lysine) side chain. The Nepsilon-substituted tetrapeptide functions as the substrate of tyrosinase and is responsible for the enzyme-mediated interpolymer cross-linking. The degree of Nepsilon-substitution (DS) was mostly controlled by changing the stoichiometry between the Nepsilon-amino groups of the parent poly(L-lysine) and the protected tetrapeptide active ester. Two kinds of samples having DS values of 8.6 and 18 mol-% were prepared. The resulting cationic Nepsilon-(Lys-Gly-Tyr-Gly)-poly(L-lysine) (abbreviated as PLL(GYGK)) was spun into hybrid fibers with the anionic polysaccharide gellan via a polyionic complexation reaction at the interface between aqueous solutions of the two polymers. The mechanical strengths of the PLL(GYGK)-gellan hybrid fibers were superior to those of the original poly(L-lysine)-gellan fibers. The mechanical strength of the hybrid fibers further increased upon the tyrosinase-mediated cross-linking reaction of the PLL(GYGK). This result indicates that the covalent cross-bridge formation between the Nepsilon-substituted peptides significantly contributed to reinforcement of the hybrid fibers. The present study affords a new methodology for reinforcement inspired by a biological process. 相似文献
970.
Ruckstuhl W Stroynowski R Atwood WB Barish BC Bonneaud GR Courau A Donaldson GJ Dubois R Duro MM Elsen EE Gao SG Huang YZ Irwin GM Johnson RP Kichimi H Kirkby J Klem DE Koop DE Ludwig J Mills GB Ogawa A Pal T Pitthan R Pollard DL Prescott CY Rochester LS Sakuda M Sherman SS Wang SQ Wojcicki SG Yamamoto H Yan WG Young CC 《Physical review letters》1986,56(20):2132-2135